ABB RELION 670 Series Applications Manual page 216

Section 8
Voltage protection
ANSI07000190 V1 EN-US
Figure 100: Ground fault in Non-effectively grounded systems
8.3.3.5 Direct grounded system
In direct grounded systems, an ground fault on one phase indicates a voltage collapse in that
phase. The two healthy phases will have normal phase-to-ground voltages. The residual sum will
have the same value as the remaining phase-to-ground voltage. See figure 101.
210
ANSI07000190-1-en.vsd
1MRK 505 337-UUS A
GUID-EA622F55-7978-4D1C-9AF7-2BAB5628070A v7
Application manual